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Homework Help: Set logic homework

  1. Aug 19, 2010 #1
    1. The problem statement, all variables and given/known data
    X={n/n belongs to N,X>=4}
    B={x belongs N/ x<5}


    2. Relevant equations
    then,
    A intersection B=________
     
  2. jcsd
  3. Aug 19, 2010 #2

    Office_Shredder

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    Re: set,logic

    Your post has several errors in it. There's no A until the final line of your post and your set X contains only elements such that X>=4 which doesn't make any sense.

    I assume your intended question is
    [tex]A= \{x\ :\ x\in \mathbb{N}\ &\ x\geq4 \}[/tex]
    [tex]B=\{x\ :\ x\in \mathbb{N}\ &\ x<5 \}[/tex]

    and you want to find [tex]A\cap B[/tex]

    You have to show what work you've done so far. How have you tried to solve the problem?
     
  4. Aug 19, 2010 #3

    HallsofIvy

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    Re: set,logic

    Assuming, as Office Shredder suggests, that your sets are
    [itex]A= \{n |n\in \mathbb{N} , \ n\ge 4\}[/itex]
    and
    [itex]B= \{n| n\in \mathbb{N} ,\ n< 5\}[/itex]

    Can you list some members of A and b? What natural numbers are greater than or equal to 4? What natural numbers are less than 5?
     
  5. Aug 20, 2010 #4
    Re: set,logic

    The problem is solved already. Look at the last post. I guess the problem right now is that you are attempting to imagine or list down the members...

    Lesson Learnt:
    Step 1 : imagine the set constraints/description
    Step 2 : List the ocntents of the set and imagine a pattern
     
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